1. Technical Field
The present invention relates to an imaging device and a method for manufacturing the same.
2. Related Art
In recent years, imaging devices have been widely used, for example, in vehicles and mobile phones, and are required to be miniaturized as they become popular. As one way to achieve miniaturization of imaging devices, there is known an imaging device having an imaging element compactly mounted on a circuit board utilizing molded interconnect device (MID) method.
An imaging device of this type known in related art is disclosed in JP-2007-102017, for example, which prevents electrical problems attributed to the condition of the joints between an MID and a circuit board being incomplete when mounting a relatively heavy lens such as a high performance wide-angle lens.
As shown in FIG. 5, an imaging device 10 disclosed in JP-2007-102017 is provided with a lens 11 having a male thread section 11a, a lens bracket 12 having the lens 11 mounted therein, a lens fixing nut 13, an imaging element 14 for converting the light passing through the lens 11 to an electrical signal, an MID 15 having the imaging element 14 mounted thereon, an MID mounting substrate 16 having the MID 15 mounted thereon, a plate spring 21 attached to the lens bracket 12, a lower case 22 constituting a part of a housing, and an upper case 23 engaged with the plate spring 21 that presses down the lens bracket 12 towards the lower case 22 as the upper case 23 is fixed to the lower case 22.
In the lens bracket 12, there are formed a female thread section 12a for accepting the lens 11, a guide groove 12b for positioning the MID 15 in a direction orthogonal to an optical axis of the lens 11 with respect to the lens bracket 12 as shown by an arrow 11A in the drawing when engaged with the MID 15, an engaging section 12c that engages with the MID mounting substrate 16, and a catch 12d for securing the plate spring 21 in place. Meanwhile, in the upper case 23, there is formed an engaging section 23a that engages with the plate spring 21 as the upper case 23 is fixed to the lower case 22. Accordingly, when the upper case 23 is fixed to the lower case 22, the MID mounting substrate 16 is pressed by the lens bracket 12 and is fixed to the lower case 22 as the section 23a of the upper case 23 engages with the plate spring 21.
The imaging device 10 in related art thus described is assembled in the following manufacturing process.
First, the lens 11 attached with the lens fixing nut 13 is inserted to the lens bracket 12. In this case, by engaging the male thread section 11a of the lens 11 with the female thread section 12a of the lens bracket 12, the lens 11 attached with the fixing nut 13 and the lens bracket 12 become unified.
Next, the imaging element 14, the MID 15, and the MID mounting substrate 16 are fixed to one another to be unified.
The plate spring 21 is then secured to the lens bracket 12 by latching the plate spring 21 to the catch 12d of the lens bracket 12.
Thereafter, the lens bracket 12 is fitted with the MID 15 along the guide groove 12b, and is engaged with the MID mounting substrate 16 at the engaging section 12c of the lens bracket 12, determining the position of the MID 15 with respect to the lens bracket 12 in the direction orthogonal to the optical axis of the lens 11.
By adjusting an engaged position of the lens 11 with respect to the lens bracket 12, the position of the lens 11 with respect to the imaging element 14 in the optical axis direction, i.e., focus position, is adjusted. After the focus is adjusted with respect to the imaging element 14, the lens 11 is secured to the lens bracket 12 with the lens fixing nut 13.
The imaging element 14, the MID 15, and the MID mounting substrate 16 fixed to the lens bracket 12 that is with the lens 11 fixed therein are then inserted to the lower case 22 as an internal component 20.
When the upper case 23 is fixed to the lower case 22 while the internal component 20 is being inserted therein, the engaging section 21a of the plate spring 21 fixed to the lens bracket 12 is pressed by the engaging section 23a of the upper case 23, and thus the internal component 20 is fixed inside the upper case 23 and the lower case 22.
In the imaging device 10 in related art structured as above, when it is applied, for example, to a vehicle-mounted camera whose mounting position is predetermined with respect to an automotive vehicle, the internal component 20 needs to be adjusted to an optimal position with respect to the lower case 22 and the upper case 23 during the manufacturing process of the imaging device 10.